The present invention is directed to drawing compasses, and more particularly, to safety drawing compasses that include movable carriage.
This application claims priority to Great Britain Application No. 9825595.3.
Compasses are widely used by both professional draftpersons and laypersons as an aid to draw arcs and circles. Most conventional compasses includes a pair of legs that are adjustably attached at a common end. One of the legs includes a tapered portion that ends in a pivot point, and the other leg is shaped to receive a writing instrument therein. In order to draw an arc, the pivot point is anchored on a paper surface, and the compass is rotated about the pivot point and while the writing instrument is passed across the surface of the paper. However, conventional compasses can be difficult to use, and the tapered portion and-pivot point may not be practical for use by children.
A xe2x80x9csafety compassxe2x80x9d typically includes generally flat body having a short, protruding pivot point, and the body includes a hole or a plurality of holes to receive a drawing instrument. In order to use the safety compass, the body of the compass is positioned flat against the paper to be drawn upon. A pen, pencil, or other drawing instrument is inserted into one of the holes, and the compass body and writing instrument are rotated about the pivot point such that the drawing instrument draws an arc on the paper.
The compass may also include a movable carriage that receives the writing instrument. The carriage is releasably coupled to the compass body to vary the radius of the arc to be drawn. The prior art mechanisms for releasably coupling the carriage to the compass body lack durability and robustness, and can be difficult to operate. Accordingly, there is a need for a safety compass including a carriage that can be releasably coupled to the body in a quick and easy operation, and wherein the compass is durable and robust.
The present invention is a drawing compass incorporating an improved mechanism for coupling the carriage to the body. In particular, the body and/or carriage each include a plurality of grooves and teeth for releasably coupling the carriage to the body. In one embodiment, the invention is a drawing compass comprising a body having a pivot point and a longitudinal slot formed therein, the longitudinal slot defining a first inner surface. The drawing compass includes a carriage received in and movable along the longitudinal slot. The carriage includes a guide to receive a writing instrument therethrough and a movable arm biased against the first inner surface. The compass further comprises means for releasably coupling the arm to the body.
Accordingly, it is an object of the present invention to provide a safety compass that is durable and robust, and that includes a carriage that can be quickly and easily uncoupled from the body of the compass.
Other objects and advantages of the present invention will be apparent from the following description and the accompanying drawings.